(a) The eating up of metals by the action of air, moisture or a chemical (such as an acid) on their surface is called corrosion.
(b) Gold and Platinum
(c) Rusting
(d) Aluminium begins to corrode quickly when it comes in contact with moist air. The action of moist air on aluminium metal forms a thin layer of aluminium oxide all over the metal. This aluminium oxide is very tough and prevents the metal underneath from further corrosion.
Therefore, aluminium is used for making utensils irrespective of its highly reactive property as its corrosion leads to the non-corrosion of the metal in the longer run.
